1. Technical Field
An aspect of the presents invention relate to an imaging element that includes a photoelectric conversion section formed by arranging a plurality of photoelectric conversion elements in matrix and performs a processing related to readout of accumulated charges with respect to a predetermined pixel line composed of the photoelectric conversion elements in plural times in a time dividing manner in one horizontal scanning period.
2. Related Art
Examples of a solid state imaging system include a CCD (charge coupled device) type image sensor (hereinafter, simply referred to as a “CCD sensor”) and a CMOS type image sensor (hereinafter, simply referred to as a “CMOS sensor”). Further, a MOS (metal oxide semiconductor) type solid state imaging system depending on a threshold voltage shift (hereinafter, simply referred to as a “substrate modulation sensor”) is also proposed. The MOS type solid state imaging system provides high picture quality and low power consumption. The CMOS sensor and the substrate modulation sensor (hereinafter, referred to as “the CMOS sensor and the like”) have been recently developed because of their low electric consumption and low processing cost compared to the CCD sensor.
The CMOS sensor and the like employ a rolling shutter mode in which a processing is performed line by line when charges accumulated in photodiodes that are photoelectric conversion elements are read out or when charges accumulated in the photodiodes are reset.
The CMOS sensor is a sensor performing a destructive readout processing or a sensor performing a nondestructive readout processing. The former always performs a shutter (reset) processing after the readout of accumulated charges. Therefore, the accumulated charges are depleted after the readout. The latter leaves the accumulated charges without resetting even after the readout, so that the readout of the accumulated charges can be performed in many times in different exposing times. Therefore, in the CMOS sensor performing a nondestructive readout, plural times of readout processings can be performed in a time dividing manner in one horizontal scanning period.
As a technique of performing such readout in a time dividing manner, JP-A-2007-194981 discloses a physical information acquisition device, for example.
The physical information acquisition device of the example sets a readout address R and drive controls for respective unit pixels of a shutter address S for setting a charge storage time in the readout address R in a time dividing manner and drives corresponding unit pixels at predetermined timing. Accordingly, addresses can be set with a common address decoding circuit. Therefore, in a case of increasing the number of time divisions, the number of the address decoding device is not required to be increased.
However, the related art of the above example needs to increase the number of circuits generating a control signal for driving an imaging section as the number of the time divisions increases.